Many kinds of roof ventilators are found in the prior art. Some of these are turbine types which are wind driven. Evacuation of crawl space or attic space air is also accomplished by fans typically mounted at opposite ends of the attic which, in some cases are thermostatically controlled.
Other types of roof ventilators are of the type which are constructed to be mounted over the elongated opening along the ridge of the building roof. In most cases, these comprise some type of sheet metal structure having vents or perforations which the sheet metal structure is secured along the ridge. Representative of these type of devices is U.S. Pat. No. 4,545,291 which shows a ventilator comprised of sheet metal having an inner baffle and flu portions and an outer storm band casing. Louvers are provided in the base and baffle portions of the side wall.
U.S. Pat. No. 3,949,657 shows a ventilated cap which is placed over the opening in the ridge of the roof and includes a pair of beveled edge vent parts. Each vent part has transversely oriented openings extending from one beveled edge to the other. The vent parts are placed side-edge-to-side-edge over the opening in the roof ridge and secured to the underlying roof sides.
The early patent to Seymour, U.S. Pat. No. 2,214,183 shows a roofing and ventilated roof structure which discloses roofing units which may be used either at the overhang of an eave or gable or may be employed as an edging course associated with the ridge.
U.S. Pat. No. 4,558,637 discloses a ventilating member having a central, inverted V-shaped portion connecting the sides. Louvers and shield portions are located adjacent to the side louvers to prevent precipitation from passing through the support member and down into the ridge roof at openings.
U.S. Pat. No. 4,573,291 discloses a ridge covering having flexible ceiling strips arranged between the covering caps fastened to the ridge or hip board and the roofing tiles.
U.S. Pat. No. 4,325,290 shows a ridge ventilator for the roof of a building which includes a porous, non-woven and fibrous filter medium selectively installed in the ventilator to prevent inadvertent infiltration of moisture through the ventilator into the space below the roof.
Other representative ventilators constructed of sheet metal and fabricated having louvers or vents are shown in U.S. Pat. Nos. 3,481,263; and 3,241,474.
One roof vent system which has been commercially utilized is that shown in U.S. Pat. No. 5,339,582 sold under the designation COR-A-VENT. This patent shows an air dam mounted on a vent having openings extending transversely and placed upon the ridge of the roof. The air dam includes an outer and upper flange and a lower leg with the outer edge of the flange being spaced from the inner surface of a covering over the roof ridge to insure proper air flow from the roof peak and to form a barrier against the ingressive wind-driven moisture downwardly into the vent openings.
While the above prior art is representative of various roof vent designs and many of these systems have been placed into commercial use, there nevertheless exists a need for an improved roof vent which will be effective to provide the necessary free vent area required by various codes and which vent system is also easy to install and relatively inexpensive to manufacture.